The present invention relates to compositions that provide care to the colors of fabrics in laundry treatment.
The appearance of colored fabrics, e.g., clothing, bedding, household fabrics like table linens is one of the areas of concern to consumers. Indeed, upon typical consumer""s uses of the fabrics such as wearing, washing, rinsing and/or tumble-drying of fabrics, a loss in the fabric appearance, which is at least partly due to loss of color shade intensity, fidelity and color definition, is observed. Such a problem of color loss is even more acute in laundry treatment after multiwash cycles, especially for dark colors, such as blacks, reds, blues, and greens.
Several mechanisms have been speculated upon for color loss and various means have been proposed to prevent or reduce the extent of the loss or transfer of color. For example, color fixatives, known in the dyeing industry have been proposed, as have agents (such as PVP) to hold color materials in solution to prevent re-deposition or to prevent abrasion between fibers. It has also been suggested to add bleaching agents to wash liquor to bleach any dye that enters solution.
One cause of color loss is the use of an inappropriate detergent composition. Thus, many manufacturers produce xe2x80x9ccolor carexe2x80x9d formulations that do not contain bleaches. Despite this, color damage remains a significant problem in the eyes of consumers.
WO 00/15746 (PandG), filed Sep. 15, 1998, published Mar. 23, 2000, discloses fabric care compositions, which comprise low molecular weight polyamines for color care. It is believed that the polyamines intercept peroxygen bleaching. A dye fixative may also be present in the compositions disclosed, as may an xe2x80x9cabrasion reducing polymerxe2x80x9d such as the N-heterocyclic polymer PVP (see examples 50-53 in table XII).
One aspect of the present invention is to provide a composition which provides improved color appearance of the laundered fabrics, especially after a single washing cycle and more especially after multiple wash cycles.
Applicants have surprisingly found that the combination of a dye fixing agent, an N-heterocyclic polymer, and a nonionic surfactant can be used as an additive in conjunction with a laundry detergent, or in a presoak step to solve the problem of dark color preservation.
One aspect of the present invention is a composition comprising a dye fixing agent, an N-heterocyclic polymer, and a nonionic surfactant. Preferably a chelating compound is added to reduce color shifting, especially for the reduction of bluing of direct red dyes when tap water containing dissolved metals such as iron, copper, and the like is used.
In another aspect of the invention, there is provided a method for providing color care to fabrics upon domestic laundering treatments which comprise the step of contacting the fabrics with the inventive composition, either in the presence of detergent or in a presoak step without detergent. In a further aspect of the invention, improvement in color shade stability and dye transfer is observed for treated fabrics, especially direct-dyed, cellulosic dark colored fabrics, even if the water temperature of the treatment is varied from cold (60 F) to hot (130 F). Direct dyed cellulosic fabrics (e.g. cotton, rayon, etc.) show substantially improved color shade retention and minimal dye transfer with the inventive composition.
The inventive fabric care composition comprises a dye fixing agent, an N-heterocyclic polymer, and a nonionic surfactant dissolved in water, a water miscible solvent, or a blend thereof. The inventive composition may also be in the form of a semisolid, powder or granule which is dissolved in an aqueous medium when ready for use. In the liquid state, preferably the dye fixing agent is present in the concentration range of 0.1 to 20 wt. %, more preferably in the concentration range of 1 to 10 wt. %. Preferably the N-heterocyclic polymer is present in the concentration range of 0.01 to 10 wt. %, more preferably in the concentration range of 0.1 to 5 wt. %.
Preferably the inventive fabric care composition further comprises a chelating agent. Preferably the chelating agent is present in the concentration range of 0.005 to 5 wt. %, more preferably in the concentration range of 0.05 to 1 wt. %. Preferably the inventive fabric care composition further comprises a nonionic surfactant. Preferably the nonionic surfactant is present in the concentration range of 0.01 to 20 wt. %, more preferably in the concentration range of 0.1 to 10 wt. %.
The inventive fabric care composition preferably contains a buffering agent to adjust the pH in the range of 7.0 to 8.5, and various adjuvants such as one or more preservatives, colorants, fragrances, and the like.
An inventive process for pretreating colored fabrics with the inventive composition is also provided which comprises the steps of presoaking the fabric by applying said composition onto the fabric in a sufficient quantity of water to wet the fabric, and allowing said composition to remain in contact with said fabric before said fabric is washed for a predetermined time as indicated below. Preferably the dye fixing agent is present in the concentration range of about 0.0008 to 0.16 wt. %, more preferably in the concentration range of about 0.008 to 0.08 wt. % in the presoak solution. Preferably the N-heterocyclic polymer is present in the concentration range of about 0.00008 to 0.08 wt. more preferably in the concentration range of about 0.0008 to 0.04 wt. % in the presoak solution. Preferably a chelating agent is present in the concentration range of about 0.00004 to 0.04 wt. %, more preferably in the concentration range of about 0.0004 to 0.008 wt. % in the presoak solution. Preferably the presoak time is in the range of about 10 minutes to 12 hours, more preferably about 10 to 60 minutes. Typically the presoak temperature is in the range of about 60 F to 90 F.
The presoak solution more preferably contains a buffering agent to adjust the pH in the range of 7.0 to 8.5 and various adjuvants such as one or more preservatives, colorants, fragrances, and the like.
An inventive process for washing colored fabrics with the inventive composition is also provided comprising the steps of adding said composition into a detergent solution for washing fabrics where said detergent solution has a concentration of surfactants in the range of about 1.0 to 0.08 wt %.
Useful detergent products typically have a concentration of surfactants in the range of about 20 to 40 wt %. Preferably the detergent surfactants includes at least one anionic surfactant selected from sodium alkyl ethoxy sulfate, sodium alkyl benzene sulfonate, primary alcohol sulfates, and the like and which are collectively present in a concentration range of about 10 to 30 wt. %.
Preferably the dye fixing agent is present in the concentration range of about 0.0001 to 0.02 wt. %, more preferably in the concentration range of about 0.001 to 0.01 wt. % in the washing solution. Preferably the N-heterocyclic polymer is present in the concentration range of about 0.00001 to 0.01 wt. %, more preferably in the concentration range of about 0.0001 to 0.005 wt. % in the washing solution. Preferably a chelating agent is present in the concentration range of about 0.000005 to 0.005 wt. %, more preferably in the concentration range of about 0.00005 to 0.001 wt. % in the washing solution.
The washing solution preferably contains a buffering agent to adjust the pH in the range of 7.0 to 9.5, and various adjuvants such as one or more preservatives, colorants, fragrances, and the like.
Dye Fixing Agents
A component of the inventive composition is a dye fixing agent. Dye fixing agents, or xe2x80x9cfixativesxe2x80x9d, are well-known, commercially available materials which are designed to improve the appearance of dyed fabrics by minimizing the loss of dye from fabrics due to washing. Not included within this definition are components which are fabric softeners.
Many dye fixing agents are cationic, and are based on various quaternized or otherwise cationically charged organic nitrogen compounds. Cationic fixatives are available under various trade names from several suppliers. Representative examples include: Tinofix CL, ECO, RTM, and RTM.FRD from Ciba-Geigy, Burcofix NF and Burcoterg from Burlington Chemical; Mirapol A-15 from Rhodia; CROSCOLOR PMF (July 1981, Code No. 7894) and CROSCOLOR NOFF (January 1988, Code No. 8544) from Crosfield; INDOSOL E-50 (Feb. 27, 1984, Ref. No. 6008.35.84; polyethyleneamine-based) from Sandoz such as SANDOFIX TPS, and SANDOFIX SWE (cationic resinous compound), REWIN SRF, REWIN SRF-O and REWIN DWR from CHT-Beitlich GMBH.
Other cationic dye fixing agents are described in xe2x80x9cAftertreatments for improving the fastness of dyes on textile fibresxe2x80x9d by Christopher C. Cook (REV. PROG. COLORATION Vol. 12, 1982). Dye fixing agents suitable for use in the present invention are ammonium compounds such as fatty acid-diamine condensates e.g. the hydrochloride, acetate, metasulphate and benzyl hydrochloride of oleyldiethyl aminoethylamide, oleylmethyldiethylenediaminemethosulphate, monostearyl-ethylene diaminotrimethylammonium methosulphate and oxidized products of tertiary amines; derivatives of polymeric alkyldiamines, polyaminecyanuric chloride condensates and aminated glycerol dichlorohydrins.
A typical amount of the dye fixing agent to be employed in the composition of the invention is preferably up to 90% by weight, preferably up to 50% by weight, more preferably from 0.1% to 20% by weight, most preferably from 1% to 10% active by weight of the composition.
N-Heterocyclic Polymers
A second component of the present invention is an N-heterocyclic polymeric dye transfer inhibiting agent. Such polymeric dye transfer inhibiting agents are normally incorporated into detergent compositions in order to inhibit the transfer of dyes from colored fabrics onto fabrics washed therewith. These polymers have the ability to complex or adsorb the fugitive dyes washed out of dyed fabrics before the dyes have the opportunity to become attached to other articles in the wash. Not included within this definition are components which are fabric softeners.
Especially suitable polymeric dye transfer inhibiting agents are PVP N-oxide polymers, copolymers of N-vinylpyrrolidone and N-vinylimidazole, polyvinylpyrrolidone polymers, polyvinyloxazolidones and polyvinylimidazoles, 4-vinyl pyridine polymers, 2-vinyl pyridine polymers or mixtures thereof, and the like. Such polymers may or may not be quaternized. Useful polymeric dye transfer inhibiting agents are described in U.S. Pat. No. 5,849,684; issued on Dec. 15, 1998 to Donoghue, et al. which is here incorporated by reference. Preferably an alkali metal or ammonium salt of Poly (N-carboxymethyl-4-vinylpyridinium) chloride such as the sodium salt, obtainable as Chromabond S-100 from ISP Chemical Corp.; or PVP homopolymer obtainable from BASF Chemical Corp. may be used.
Chelating Agents
The inventive composition may also optionally contain one or more transition-metal selective sequestrants or xe2x80x9cchelating agentsxe2x80x9d, e.g., iron and/or copper and/or manganese chelating agents, provided that such materials are compatible or suitably formulated. Chelating agents suitable for use herein can be selected from the group consisting of aminocarboxylates, iminodisuccinates, hydroxycarboxylates (especially citrates), phosphonates (especially the aminophosphonates), polyfunctionally-substituted aromatic chelating agents, phosphates, and mixtures thereof. Without intending to be bound by theory, it is believed that the benefit of these materials is due in part to their exceptional ability to remove iron, copper and manganese ions from washing solutions by formation of soluble chelates. Commercial chelating agents for use herein include iminodisuccinate TP(copyright) from Bayer; DEQUEST(trademark) series, and chelants from Monsanto, DuPont, and Nalco, Inc.
Aminocarboxylates useful as optional chelating agents are further illustrated by ethylenediaminetetracetates, N-hydroxyethylethylenediaminetriacetates, nitrilotriacetates, ethylenediamine tetraproprionates, triethylenetetraaminehexacetates, diethylenetriaminepentaacetates, and ethanoldiglycines, alkali metal, ammonium, and substituted ammonium salts thereof. Polyfunctionally-substituted aromatic chelating agents are also useful in the compositions herein. See U.S. Pat. No. 3,812,044, issued May 21, 1974, to Connor et al. and U.S. Pat. No. 6,099,587, issued Aug. 8, 2000 to Scialla et al.; both of which are here incorporated by references for further useful examples.
Aminophosphonates are also suitable for use as chelating agents in the compositions of the invention when at least low levels of total phosphorus are permitted in detergent compositions, and include the ethylenediaminetetrakis (methylenephosphonates) and the diethylenetriaminepentakis (methylenephosphonates). If utilized, chelating agents or transition-metal-selective sequestrants will preferably comprise from about 0.001% to about 10%, more preferably from about 0.05% to about 1% by weight of the compositions herein.
Carboxymethyloxy succinates, and alkali metal, ammonium, substituted ammonium and alkanolamine salts thereof are also suitable for use as chelating agents in the composition of the invention. See U.S. Pat. No. 3,692,685, issued Sep. 19, 1972 to Lamberti et al., which is here incorporated by reference.
Nonionic Surfactants
A third component of the inventive fabric care composition is a nonionic surfactant. One class of nonionic surfactants useful in the present invention are condensates of ethylene oxide with a hydrophobic moiety to provide a surfactant having an average hydrophilic-lipophilic balance (HLB) in the range from 8 to 17, preferably from 8.5 to 13.5, more preferably from 10 to 13.3. The hydrophobic (lipophilic) moiety may be aliphatic or aromatic in nature and the length of the polyoxyethylene group which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements.
Especially preferred nonionic surfactants of this type are the C9-C15 primary alcohol ethoxylates containing 3-10 moles of ethylene oxide per mole of alcohol, particularly the C12-C15 primary alcohols containing 6-9 moles of ethylene oxide per mole of alcohol and the C12-C14 primary alcohols containing 5-9 moles of ethylene oxide per mole of alcohol.
Another class of nonionic surfactants comprises alkyl polyglucoside compounds of general formula
RO (Cn H2n O)t Zx 
wherein Z is a moiety derived from glucose; R is a saturated hydrophobic alkyl group that contains from 12 to 18 carbon atoms; t is from 0 to 10 and n is 2 or 3; x is from 1.3 to 4, the compounds including less than 10% unreacted fatty alcohol and less than 50% short chain alkyl polyglucosides. Compounds of this type and their use in detergents are disclosed in U.S. Pat. No. 4,536,317 issued on Aug. 20, 1985 to Llenado et al.; U.S. Pat. No. 4,483,779 issued on Nov. 20, 1984 to Llenado et al.; and U.S. Pat. No. 4,493,773 issued on Jan. 15, 1985; all of which are here incorporated by reference.
Also suitable as nonionic surfactants are poly hydroxy fatty acid amide surfactants of the formula R2(CO)N(R1)Z wherein R1 is H, or R1 is C1-4 hydrocarbyl, 2-hydroxy ethyl, 2-hydroxy propyl or a mixture thereof, R2 is C5-31 hydrocarbyl, and Z is a polyhydroxyhydrocarbyl having a linear hydrocarbyl chain with at least 3 hydroxyls directly connected to the chain, or an alkoxylated derivative thereof. Preferably, R1 is methyl, R2 is a straight C11-15 alkyl or alkenyl chain such as coconut alkyl or mixtures thereof, and Z is derived from a reducing sugar such as glucose, fructose, maltose, lactose, in a reductive amination reaction.
Other suitable nonionic surfactants include long chain amine oxides, long chain phosphonic oxides, and dialkyl sulfoxides.
Fabric Evaluation Methods
The color care benefit with regard to shade stability and color shifting may either be assessed visually by a trained panel or by determination of the so-called delta-E values, or by other art recognized techniques.
When visual assessment is used, a panel of expert graders visually compare fabrics treated with and without the composition according to the present invention and variations thereof. Each panelist assigns 5 points for the least faded example, 4 points for the next best, and so on when 5 samples are being compared. The rank scores for all the panelists are then summed and compared with each other. The maximum points to be assigned is set to equal the number of samples to be compared.
Other useful methods for the assessment of the color care benefit to fabrics is the determination of the so-called delta-E values. Delta E""s are defined, for instance, in ASTM D2244. Delta E is the computed color difference as defined in ASTM D2244, i.e. the magnitude and direction of the difference between two psychophysical color stimuli defined by tristimulus values, or by chromaticity coordinates and luminance factor, as computed by means of a specified set of color-difference equations defined in the CIE 1976 CIELAB opponent-color space, the Hunter opponent-color space, the Friele-Mac Adam-Chickering color space or any equivalent color space.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material ought to be understood as modified by the word xe2x80x9caboutxe2x80x9d.
The following examples will more fully illustrate the embodiments of this invention. All parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise illustrated.
The following Heavy Duty Liquid (HDL) Detergent formulations were tested with the inventive composition as follows: